The field of this invention is that of automotive vapor canisters and the invention relates more particularly to covers for such canisters adapted to heat air which is periodically introduced into the canisters for purging the filter materials in the canister.
Automotive vapor canisters are conventionally arranged to receive fuel vapors from fuel tanks and from carburetors or comparable engine components during some periods of the automotive vehicle use cycle for filtering the vapors through carbon filter particles to release only vapor-free air to the surrounding atmosphere. The filter particles are periodically purged of vapors by passing air back through the carbon filter particles into the carburetor or other portion of the engine intake during engine operation so hydrocarbons purged from the canister are consumed by the engine. It has been known that removal of hydrocarbons from the carbon particles requires heating of the purging air for achieving desirable canister purging efficiency and it is found that the provision of electric heating for such canister purging air as previously proposed has tended to result in bulky or expensive canister heater structures and has resulted in a significant drain on available automotive electric power in competing for available power with the power required for all other vehicle electrical loads.